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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
3bd5a5fc AH |
2 | #include <stdbool.h> |
3 | #include <errno.h> | |
4 | ||
5 | #include <linux/perf_event.h> | |
6 | ||
7 | #include "../../perf.h" | |
d944c4ee | 8 | #include <linux/types.h> |
3bd5a5fc | 9 | #include "../../util/debug.h" |
0b437860 | 10 | #include "../../util/tsc.h" |
3bd5a5fc | 11 | |
3bd5a5fc AH |
12 | int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc, |
13 | struct perf_tsc_conversion *tc) | |
14 | { | |
fa731587 | 15 | bool cap_user_time_zero; |
3bd5a5fc AH |
16 | u32 seq; |
17 | int i = 0; | |
18 | ||
19 | while (1) { | |
20 | seq = pc->lock; | |
21 | rmb(); | |
22 | tc->time_mult = pc->time_mult; | |
23 | tc->time_shift = pc->time_shift; | |
24 | tc->time_zero = pc->time_zero; | |
fa731587 | 25 | cap_user_time_zero = pc->cap_user_time_zero; |
3bd5a5fc AH |
26 | rmb(); |
27 | if (pc->lock == seq && !(seq & 1)) | |
28 | break; | |
29 | if (++i > 10000) { | |
30 | pr_debug("failed to get perf_event_mmap_page lock\n"); | |
31 | return -EINVAL; | |
32 | } | |
33 | } | |
34 | ||
fa731587 | 35 | if (!cap_user_time_zero) |
3bd5a5fc AH |
36 | return -EOPNOTSUPP; |
37 | ||
38 | return 0; | |
39 | } | |
a6a69db4 AH |
40 | |
41 | u64 rdtsc(void) | |
42 | { | |
43 | unsigned int low, high; | |
44 | ||
45 | asm volatile("rdtsc" : "=a" (low), "=d" (high)); | |
46 | ||
47 | return low | ((u64)high) << 32; | |
48 | } | |
46bc29b9 AH |
49 | |
50 | int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc, | |
51 | struct perf_tool *tool, | |
52 | perf_event__handler_t process, | |
53 | struct machine *machine) | |
54 | { | |
55 | union perf_event event = { | |
56 | .time_conv = { | |
57 | .header = { | |
58 | .type = PERF_RECORD_TIME_CONV, | |
59 | .size = sizeof(struct time_conv_event), | |
60 | }, | |
61 | }, | |
62 | }; | |
63 | struct perf_tsc_conversion tc; | |
64 | int err; | |
65 | ||
c45628b0 WN |
66 | if (!pc) |
67 | return 0; | |
46bc29b9 AH |
68 | err = perf_read_tsc_conversion(pc, &tc); |
69 | if (err == -EOPNOTSUPP) | |
70 | return 0; | |
71 | if (err) | |
72 | return err; | |
73 | ||
74 | pr_debug2("Synthesizing TSC conversion information\n"); | |
75 | ||
76 | event.time_conv.time_mult = tc.time_mult; | |
77 | event.time_conv.time_shift = tc.time_shift; | |
78 | event.time_conv.time_zero = tc.time_zero; | |
79 | ||
80 | return process(tool, &event, NULL, machine); | |
81 | } |